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        "\n# Faces recognition example using eigenfaces and SVMs\n\n\nThe dataset used in this example is a preprocessed excerpt of the\n\"Labeled Faces in the Wild\", aka LFW_:\n\n  http://vis-www.cs.umass.edu/lfw/lfw-funneled.tgz (233MB)\n\n\nExpected results for the top 5 most represented people in the dataset:\n\n================== ============ ======= ========== =======\n                   precision    recall  f1-score   support\n================== ============ ======= ========== =======\n     Ariel Sharon       0.67      0.92      0.77        13\n     Colin Powell       0.75      0.78      0.76        60\n  Donald Rumsfeld       0.78      0.67      0.72        27\n    George W Bush       0.86      0.86      0.86       146\nGerhard Schroeder       0.76      0.76      0.76        25\n      Hugo Chavez       0.67      0.67      0.67        15\n       Tony Blair       0.81      0.69      0.75        36\n\n      avg / total       0.80      0.80      0.80       322\n================== ============ ======= ========== =======\n\n\n"
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      "source": [
        "from time import time\nimport logging\nimport matplotlib.pyplot as plt\n\nfrom sklearn.model_selection import train_test_split\nfrom sklearn.model_selection import GridSearchCV\nfrom sklearn.datasets import fetch_lfw_people\nfrom sklearn.metrics import classification_report\nfrom sklearn.metrics import confusion_matrix\nfrom sklearn.decomposition import PCA\nfrom sklearn.svm import SVC\n\n\nprint(__doc__)\n\n# Display progress logs on stdout\nlogging.basicConfig(level=logging.INFO, format='%(asctime)s %(message)s')\n\n\n# #############################################################################\n# Download the data, if not already on disk and load it as numpy arrays\n\nlfw_people = fetch_lfw_people(min_faces_per_person=70, resize=0.4)\n\n# introspect the images arrays to find the shapes (for plotting)\nn_samples, h, w = lfw_people.images.shape\n\n# for machine learning we use the 2 data directly (as relative pixel\n# positions info is ignored by this model)\nX = lfw_people.data\nn_features = X.shape[1]\n\n# the label to predict is the id of the person\ny = lfw_people.target\ntarget_names = lfw_people.target_names\nn_classes = target_names.shape[0]\n\nprint(\"Total dataset size:\")\nprint(\"n_samples: %d\" % n_samples)\nprint(\"n_features: %d\" % n_features)\nprint(\"n_classes: %d\" % n_classes)\n\n\n# #############################################################################\n# Split into a training set and a test set using a stratified k fold\n\n# split into a training and testing set\nX_train, X_test, y_train, y_test = train_test_split(\n    X, y, test_size=0.25, random_state=42)\n\n\n# #############################################################################\n# Compute a PCA (eigenfaces) on the face dataset (treated as unlabeled\n# dataset): unsupervised feature extraction / dimensionality reduction\nn_components = 150\n\nprint(\"Extracting the top %d eigenfaces from %d faces\"\n      % (n_components, X_train.shape[0]))\nt0 = time()\npca = PCA(n_components=n_components, svd_solver='randomized',\n          whiten=True).fit(X_train)\nprint(\"done in %0.3fs\" % (time() - t0))\n\neigenfaces = pca.components_.reshape((n_components, h, w))\n\nprint(\"Projecting the input data on the eigenfaces orthonormal basis\")\nt0 = time()\nX_train_pca = pca.transform(X_train)\nX_test_pca = pca.transform(X_test)\nprint(\"done in %0.3fs\" % (time() - t0))\n\n\n# #############################################################################\n# Train a SVM classification model\n\nprint(\"Fitting the classifier to the training set\")\nt0 = time()\nparam_grid = {'C': [1e3, 5e3, 1e4, 5e4, 1e5],\n              'gamma': [0.0001, 0.0005, 0.001, 0.005, 0.01, 0.1], }\nclf = GridSearchCV(\n    SVC(kernel='rbf', class_weight='balanced'), param_grid\n)\nclf = clf.fit(X_train_pca, y_train)\nprint(\"done in %0.3fs\" % (time() - t0))\nprint(\"Best estimator found by grid search:\")\nprint(clf.best_estimator_)\n\n\n# #############################################################################\n# Quantitative evaluation of the model quality on the test set\n\nprint(\"Predicting people's names on the test set\")\nt0 = time()\ny_pred = clf.predict(X_test_pca)\nprint(\"done in %0.3fs\" % (time() - t0))\n\nprint(classification_report(y_test, y_pred, target_names=target_names))\nprint(confusion_matrix(y_test, y_pred, labels=range(n_classes)))\n\n\n# #############################################################################\n# Qualitative evaluation of the predictions using matplotlib\n\ndef plot_gallery(images, titles, h, w, n_row=3, n_col=4):\n    \"\"\"Helper function to plot a gallery of portraits\"\"\"\n    plt.figure(figsize=(1.8 * n_col, 2.4 * n_row))\n    plt.subplots_adjust(bottom=0, left=.01, right=.99, top=.90, hspace=.35)\n    for i in range(n_row * n_col):\n        plt.subplot(n_row, n_col, i + 1)\n        plt.imshow(images[i].reshape((h, w)), cmap=plt.cm.gray)\n        plt.title(titles[i], size=12)\n        plt.xticks(())\n        plt.yticks(())\n\n\n# plot the result of the prediction on a portion of the test set\n\ndef title(y_pred, y_test, target_names, i):\n    pred_name = target_names[y_pred[i]].rsplit(' ', 1)[-1]\n    true_name = target_names[y_test[i]].rsplit(' ', 1)[-1]\n    return 'predicted: %s\\ntrue:      %s' % (pred_name, true_name)\n\nprediction_titles = [title(y_pred, y_test, target_names, i)\n                     for i in range(y_pred.shape[0])]\n\nplot_gallery(X_test, prediction_titles, h, w)\n\n# plot the gallery of the most significative eigenfaces\n\neigenface_titles = [\"eigenface %d\" % i for i in range(eigenfaces.shape[0])]\nplot_gallery(eigenfaces, eigenface_titles, h, w)\n\nplt.show()"
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